1. Field of the Invention
This invention relates to novel cephalosporin compounds and pharmaceutically acceptable salts thereof, and to a process for preparing such compounds and salts. More particularly, the invention relates to cephalosporin compounds of the following formulas (I) and (II), or pharmaceutically acceptable salts thereof, and to processes for preparing such compounds or salts.
2. Description of the Prior Art
Cephalosporin type compounds have antibacterial activities and many derivatives thereof have been produced hitherto.
Some of the cephalosporin compounds such as cephalotin, cephalexin, cefazolin, cephaloridine, etc., are used therapeutically as an excellent antibacterial agent.
Recently, a research on cephalosporin compounds aims to develop a useful compound against Gram-negative bacteria, especially Pseudomonas aeruginosa, and bacteria which have a lactamase. However, very few cephalosporin compounds exhibit satisfactory antibacterial activity against said bacteria.
Resembled compounds of this invention are disclosed in Journal of Antibiotics, Vol. 32, No. 6, page 621 (1979), but do not exhibit satisfactory antibacterial activity against said bacteria.